This invention relates to mechanical servicing of internal combustion engines and more particularly to fixturing and process for pressurizing the cylinders of an internal combustion piston engine so as to enable repair and adjustment of the overhead valve components, and to conduct certain diagnostic procedures on the valving, piston rings and head gaskets.
It has heretofore been known to apply compressed air within each of the cylinders of an internal combustion engine. This pressurization causes the engine valves to be forced onto their seats. This in turn allows the replacement of the valve springs, tappets and other valving components.
In this prior art practice, a special fitting has been employed connected to the end of an air hose which allows the air hose to be connected to a spark plug opening. This procedure was followed for each cylinder with connection and disconnection of the air hose.
An alternative approach is disclosed in U.S. Pat. No. 4,292,141 in which a bladder is inserted into the spark plug opening with a compressible bulb being connected thereto with a hose for manual inflation of the bladder. Similarly, the arrangement disclosed in that patent contemplates a cylinder-by-cylinder pressurization.
A cylinder-by-cylinder procedure is relatively inefficient as it requires connection and disconnection of the air hose each time a single set of valves is worked on.
Furthermore, the application of high pressure compressed air within the engine cylinder may cause the engine to be inadvertently rotated by the pressure on the piston, if a given piston is in a raised position. This is a greater possibility if all of the spark plugs have been removed from the engine and presents a possible hazard which desirably should be avoided.
Also, it would be highly desirable for any tooling utilized in this procedure to be adaptable to various types and models of engines, i.e., V-8, V-6 and straight four, and engines using different spark plug sizes.
It is also desirable that mechanics' tools be relatively simple and expeditiously usable, such as to improve the efficiency of the mechanic utilizing the equipment.
It is often necessary to perform leakage tests on the valves, piston rings and head gasket. This is normally done by inserting a compression tester successively in each spark plug opening and cranking the engine until the top dead center position is reached for the particular piston. Thus, this also requires a cylinder-by-cylinder procedure, and cranking of the engine to reach top dead center for each individual cylinder.
Accordingly, it is an object of the present invention to provide fixturing and a process for simultaneously pressurizing a plurality of the engine cylinders of the piston type internal combustion engine so as to enable work to be performed on several cylinders without interruption.
It is a further object of the present invention to provide such fixturing which may be adapted to either four, six or eight cylinder engines.
It is another object of the present invention to enable the appropriate cylinders to be simultaneously pressurized by the fixturing to produce a pressure balanced condition and without necessitating different fixturing for each engine type and model.
It is another object of the present invention to provide an improved fixturing and process for detection of engine, valve, cylinder head gasket, and piston ring leaks enabling more rapid and expeditious testing.
It is yet another object of the present invention to provide such fixturing which is simple to use and of rugged construction and able to be manufactured at a low cost.